The cryptocurrency industry has long feared the day when computers will be able to crack blockchains and take down networks like Bitcoin and Ethereum; that day may be closer than they think—but even at today’s supercomputer speeds, only quantum computers could have that potential.

Last week, researchers from the Lawrence Livermore National Laboratory announced that their latest supercomputer, El Capitan, is able to conduct 2.79 quadrillion calculations per second, making it the world’s fastest computer.